Abstract: A large size Split Hopkinson Pressure Bar (SHPB) of 75mm was used to study the dynamic mechanical behavior of fiber reinforced high strength concrete under an impact loading. The impact compression experiments with three different strain rate ranges were conducted for steel fiber reinforced high strength concrete specimens and polyvinyl alcohol fiber (PVA) reinforced high strength concrete specimens with three fiber contents. The results show that at high strain rate, the dynamic stress-strain relationships are strain rate dependent. It means that the fiber reinforced high strength concrete is sensitive to the strain rate. The failure stress and failure strain increase with increasing the strain rate. The energy absorbing capability of the steel fiber and PVA fiber in concrete is exhibited in the process of the material failure only after the peak stress is reached. The mechanism of the toughness increasing effect and energy absorbing of fiber reinforced high strength concrete is also analyzed and discussed.